/*
 * Copyright 2010 - 2011, The PLDesktop Development Team
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 *
 */

#include <stdlib.h>
#include <errno.h>
#include <ctype.h>
#include <unconst.h>
#include <limits.h>

extern "C" long strtol(const char *str, char **endptr, int base) {
    const char *s = str;
    unsigned long acc;
    int c;
    unsigned long cutoff;
    int neg = 0, any, cutlim;
    do {
        c = *s++;
    } while (isspace(c & 0xff));
    if(c == '-') {
        neg = 1;
        c = *s++;
    } else if(c == '+') {
        c = *s++;
    }
    if((base == 0 || base == 16) && c == '0' && (*s == 'x' || *s == 'X')) {
        c = s[1];
        s += 2;
        base = 16;
    }
    if(base == 0) {
        base = c == '0' ? 8 : 10;
    }
    cutoff = neg ? -(unsigned long)LONG_MIN : LONG_MAX;
    cutlim = cutoff % (unsigned long)base;
    cutoff /= (unsigned long)base;
    for(acc = 0, any = 0;; c = *s++, c &= 0xff) {
        if(isdigit(c)) {
            c -= '0';
        } else if(isalpha(c)) {
            c -= isupper(c) ? 'A' - 10 : 'a' - 10;
        } else {
            break;
        }
        if(c >= base) {
            break;
        }
        if(any < 0 || acc > cutoff || (acc == cutoff && c > cutlim)) {
            any = -1;
        } else {
            any = 1;
            acc *= base;
            acc += c;
        }
    }
    if(any < 0) {
        acc = neg ? LONG_MIN : LONG_MAX;
        errno = ERANGE;
    } else if(neg) {
        acc = -acc;
    }
    if(endptr != 0) {
        *endptr = any ? unconst(s, char *) - 1 : unconst(str, char *);
    }
    return acc;
}
